In this paper, starting from transport theory, estimated functions of Monte carlo direct analogue and statistical estimation have been obtained by means of term wise integration. We deal with variations of transmissivity and reflectivity in optical thickness τ, albedo of a single partical a, and anisotropy g when plane wave passes through a layer discrete random media. The results of statistical estimation method are in good agreement with those given in reference 2. As a result of considerable statistical fluctuation of scattering point samples in direct analogue method, the deviation of calculation would be larger as the optical thickness increases or anisotropic scattering or absorption becomes stronger.